Dry etch rate reduction of silicon nitride films

ABSTRACT

Embodiments described herein relate to methods of forming silicon nitride films. In one embodiment, a first process gas set including a silicon-containing gas and a first nitrogen-containing gas is flowed into the process chamber. An initiation layer is deposited by applying a first radio frequency power to the first process gas set at a first frequency and a first power level. The first flow of the first nitrogen-containing gas of the first process gas set is discontinued and a second process gas set including the silicon-containing gas, a second nitrogen-containing gas, and a hydrogen-containing gas is flowed into the process chamber. A bulk silicon nitride layer is deposited on the initiation layer by applying a second RF power to the second process gas set at a second frequency higher than the first frequency and a second power level higher than the first power level.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims benefit of U.S. Provisional Patent ApplicationSer. No. 62/589,432, filed Nov. 21, 2017, which is herein incorporatedby reference.

BACKGROUND Field

Embodiments of the present disclosure generally relate to formingsilicon nitride hard masks. More particularly, embodiments of thepresent disclosure relate to a method of forming a silicon nitride hardmask using plasma-enhanced chemical vapor deposition (PECVD) processes.

Description of the Related Art

Semiconductor device processing is used to create integrated circuitsthat are present in electrical devices. In the fabrication of integratedcircuits, deposition processes are used to deposit layers of variousmaterials upon semiconductor substrates. In order to form features onthe substrates, etch processes are used to remove portions of substratesand/or dielectric layers deposited on substrates.

Hard masks are used for etching deep, high aspect ratio features withhigh resolutions that conventional photoresists cannot withstand. Priorto etching, hard masks are deposited over substrates and/or depositeddielectric layers. The hard masks are used as barrier layers whenunderlying layers to be etched have etch rates similar to photoresistsused to pattern substrates or deposited dielectric layers. Hard maskshave properties different from the underlying layers to be etched inorder to protect portions of the underlying layers that are not to beremoved. A pattern is defined in the silicon nitride hard mask usingstandard photolithographic techniques. Then, the hard mask is etched byplasma etching, gas etching, physical dry etching, or chemical dryetching to define a pattern in the silicon nitride by exposing regionswhich are to become the features. As the minimum feature sizes ofintegrated circuits continue to decrease, an improved process is neededto form films, for use as hard masks, that resist erosion and patternchanges to provide integrated circuits with features that have smoothsurfaces and sidewalls. Thus, hard masks with high selectivity, low etchrates, and low bowing deltas are needed.

The selectivity, etch rates, and bowing deltas of a silicon nitride hardmasks are optimized based on density and refractive index. Moreover,silicon nitride hard masks with a high compressive stress are dense andnitrogen-rich, and current plasma-enhanced chemical vapor deposition(PECVD) processes cannot form silicon nitride films to be used as hardmasks that are dense and nitrogen-rich. As a result of high depositionrates, current PECVD processes form silicon nitride hard masks withsignificantly higher etch rates, lower selectivity, and higher bowingdeltas than silicon nitride hard masks formed from atomic layerdeposited films (ALD). However, silicon nitride films formed from ALDhave a higher cost and have a lower throughput than films formed fromPECVD. Therefore, an improved process is needed form films siliconnitride films a high density and refractive index.

SUMMARY

In one embodiment, a method for forming a silicon nitride film isprovided. The method includes disposing a substrate including a surfacein a chamber, flowing a silicon-containing gas and a firstnitrogen-containing gas into the chamber at a first total flow rate,depositing a silicon and nitrogen containing layer on the surface of thesubstrate by applying a first radio frequency (RF) power at a firstpower level to the silicon-containing gas and the firstnitrogen-containing gas, discontinuing the flow of thesilicon-containing gas and the first nitrogen-containing gas and flowinga second nitrogen-containing gas into the chamber, and treating thesilicon and nitrogen containing layer by applying a second RF power tothe second nitrogen-containing gas at a second power level higher thanthe first power level. A flow rate of the second nitrogen-containing gasis higher than the first total flow rate. The flowing thesilicon-containing gas and the first nitrogen-containing gas, thedepositing the silicon and nitrogen containing layer, the discontinuingthe flow of the silicon-containing gas and the first nitrogen-containinggas and the flowing the second nitrogen-containing gas, and the treatingthe silicon and nitrogen containing layer is repeated until a film witha predetermined thickness is formed.

In another embodiment, a method for forming a silicon nitride film isprovided. The method includes disposing a substrate including a surfacein a chamber, flowing a first process gas set including asilicon-containing gas and a first nitrogen-containing gas into thechamber, depositing an initiation layer on the surface of the substrateby applying a third radio frequency (RF) power to the first process gasset at a second frequency and a third power level, discontinuing theflowing the first nitrogen-containing gas of the first process gas setand flowing a second process gas set including the silicon-containinggas, a second nitrogen-containing gas, and a hydrogen-containing gasinto the chamber, and depositing a bulk silicon nitride layer on theinitiation layer by applying a first RF power to the second process gasset at a first frequency higher than the second frequency and a firstpower level higher than the third power level. The first process gas setis diatomic hydrogen gas-free and the second process gas set is diatomicnitrogen gas-free.

In yet another embodiment, a method for forming a silicon nitride filmis provided. The method includes disposing a substrate including asurface in a chamber, flowing a first process gas set including asilicon-containing gas and a first nitrogen-containing gas into thechamber at a first total flow rate, depositing a silicon and nitridecontaining layer on the surface of the substrate by applying a firstradio frequency (RF) power to the first process gas set at a firstfrequency of 10 megahertz (MHz) and 20 MHz and a first power level ofabout 50 Watts (W) to about 100 W for a duration of about 1 second toabout 5 seconds at a first pressure of the chamber less than 8 torr,discontinuing the flow of first process gas set, flowing a secondprocess gas set including a second nitrogen-containing gas into thechamber at a second total flow rate, treating the silicon and nitrogencontaining layer by applying a second RF power at the first frequencyand a second power level of about 80 W to about 120 W to the secondprocess gas set for a duration of about 5 second to 15 seconds at asecond pressure of the chamber. The second total flow rate is higherthan the first total flow rate, the second power level is higher thanthe first power level, and the first pressure of the chamber is higherthan the second pressure of the chamber. The flowing the first processgas set, the depositing the silicon and nitride containing layer, thediscontinuing the flow of the first process gas set, the flowing thesecond process gas set, and the treating of the silicon and nitrogencontaining layer is repeated until a first initiation layer with apredetermined thickness is formed. The flow of the second process gasset is discontinued and a third process gas set including thesilicon-containing gas, a third nitrogen-containing gas, and ahydrogen-containing gas is flowed into the chamber. The third processgas set is diatomic nitrogen gas-free. A bulk silicon nitride layer isdeposited on the first initiation layer by applying the first RF powerto the third process gas set at the first frequency and the first powerlevel for a duration of about 200 to about 300 seconds at a thirdpressure of the chamber. The second pressure of the chamber is higherthan the third pressure of the chamber.

BRIEF DESCRIPTION OF THE DRAWINGS

So that the manner in which the above recited features of the presentdisclosure can be understood in detail, a more particular description ofthe disclosure, briefly summarized above, may be had by reference toembodiments, some of which are illustrated in the appended drawings. Itis to be noted, however, that the appended drawings illustrate onlyexemplary embodiments and are therefore not to be considered limiting ofscope, as the disclosure may admit to other equally effectiveembodiments.

FIG. 1 is a schematic cross-sectional view of a plasma-enhanced chemicalvapor deposition chamber according to an embodiment of the disclosure.

FIG. 2 is a flow diagram of forming a silicon nitride film by cyclicdeposition-treatment according to an embodiment of the disclosure.

FIG. 3 is a flow diagram of forming a silicon nitride film by bulkdeposition according to an embodiment of the disclosure.

FIG. 4 is a flow diagram of forming a silicon nitride film by combiningcyclic deposition-treatment and bulk deposition according to anembodiment of the disclosure.

To facilitate understanding, identical reference numerals have beenused, where possible, to designate identical elements that are common tothe figures. It is contemplated that elements and features of oneembodiment may be beneficially incorporated in other embodiments withoutfurther recitation.

DETAILED DESCRIPTION

The present disclosure provides methods for forming silicon nitridefilms using PECVD processes. The films may be deposited such that theyhave a high compressive stress. Varying the flow of process gasses andRF powers over time, as described herein, provides silicon nitride filmswith high selectivity, low etch rates, and low bowing deltas needed.

FIG. 1 is a schematic cross-sectional view of a PECVD chamber 100utilized for methods for forming silicon nitride films. One example ofthe chamber 100 is a PRODUCER® chamber manufactured by AppliedMaterials, Inc., located in Santa Clara, Calif. It is to be understoodthat the PECVD chamber described below is an exemplary PECVD chamber andother PECVD chambers, including PECVD chambers from other manufacturers,may be used with or modified to accomplish aspects of the presentdisclosure.

The chamber 100 has a chamber body 102 that includes a processing volume104 that includes a substrate support 106 disposed therein to support asubstrate 101. The substrate support 106 includes a heating element 110and a mechanism (not shown) that retains the substrate 101 on a supportsurface 107 of the substrate support 106, such as an electrostaticchuck, a vacuum chuck, a substrate retaining clamp, or the like. Thesubstrate support 106 is coupled to and movably disposed in theprocessing volume 104 by a stem 108 connected to a lift system (notshown) that moves the substrate support 106 between an elevatedprocessing position and a lowered position that facilitates transfer ofthe substrate 101 to and from the chamber 100 through an opening 112.

The chamber 100 includes a flow controller 118, such as a mass flowcontrol (MFC) device, disposed between the a gas source 116 and thechamber body 102 to control a flow rate of process gasses from the gassource 116 to a showerhead 114 used for distributing the process gassesacross the processing volume 104. The showerhead 114 is connected to aRF power source 122 by a RF feed 124 for generating a plasma in theprocessing volume 104 from the process gasses. The RF power source 122provides RF energy to the showerhead 114 to facilitate generation of aplasma between the showerhead 114 and the substrate support 106. Thestem 108 is configured to move the substrate support 106 to an elevatedprocessing position at a process distance 126 between the supportsurface 107 and the showerhead 114. A vacuum pump 120 is coupled to thechamber body 102 for controlling the pressure within the processingvolume 104. A controller 128 is coupled to the chamber 100 andconfigured to control aspects of the chamber 100 during processing.

FIG. 2 is a flow diagram of a method 200 for forming a film tailored tothe properties of an underlying layer, the use of the film as a hardmask, and the etch chemistries to be used on the film. To facilitateexplanation, FIG. 2 will be described with reference to FIG. 1. However,it is to be noted that a chamber other than chamber 100 of FIG. 1 may beutilized in conjunction with method 200.

At operation 201, a substrate 101 including a surface is disposed in achamber 100. In one embodiment, the substrate 101 is disposed on thesupport surface 107 of the substrate support 106, the support surface107 at a process distance 126 from the showerhead 114. The processdistance 126 is about 250 millimeters (mm) to about 350 mm. The processdistance 126 increases ion bombardment to densify the film. In oneembodiment, the substrate support is heated to about 300 degrees Celsius(° C.) to about 500° C.

At operation 202, a silicon-containing gas and a firstnitrogen-containing gas are flowed into the chamber 100 at a first totalflow rate. In one embodiment, the flow controller 118 controls the firstflow rate of the silicon-containing gas and the firstnitrogen-containing gas from the gas source 116 and the showerhead 114distributes the silicon-containing gas and the first nitrogen-containinggas across the processing volume 104. The silicon-containing gas caninclude silane (SH₄), and/or dimers and oligomers of silane, and theflow rate of the silicon-containing gas may be about 10 standard cubiccentimeters per minute (sccm) to about 50 sccm. The firstnitrogen-containing gas includes ammonia (NH₃) and/or diatomic nitrogengas (N₂). In some embodiments, the ammonia of the firstnitrogen-containing gas is flowed at a flow rate of about 30 sccm toabout 1500 sccm and the diatomic nitrogen gas of the firstnitrogen-containing gas is flowed at a flow rate of about 500 sccm toabout 3000 sccm. In the chamber 100, a space velocity (spacevelocity=(sccm of gas flow)/(cc of process volume)) of thesilicon-containing gas is about 0.003 min⁻¹ to about 0.4 min⁻¹, a spacevelocity of the NH₃ of the first nitrogen-containing gas is about 0.25min⁻¹ to about 10 min⁻¹, and/or a space velocity of the N₂ of the firstnitrogen-containing gas is about 0.35 min⁻¹ to about 19 min⁻¹. In oneembodiment, at operation 202, argon (Ar) is flowed at a first argon flowrate of 2000 sccm to about 4000 sccm and diatomic hydrogen gas (H₂) isflowed at a first hydrogen gas flow rate of about 500 sccm to about 1500sccm to the chamber 100.

At operation 203, a silicon and nitrogen containing layer of about 5 Åto 50 Å is deposited. During the deposition, a first radio frequency(RF) power at a first frequency and a first power level is applied tothe silicon-containing gas and the first nitrogen-containing gas toionize the silicon-containing gas and the first nitrogen-containing gas.In one embodiment, the RF power source 122 provides RF energy to theshowerhead 114 to facilitate generation of plasma between the showerhead114 and the substrate support 106. The first RF power may be applied forabout 1 second to about 8 seconds at first pressure of the chamber,which is less than about 6 torr. The first frequency may be 10 MHz toabout 20 MHz. The first power level is in a range of about 50 W to about100 W. The first RF power is applied at a power density (powerdensity=power(W)/surface area of the substrate(cm²)) of about 0.05 W/cm²to about 0.35 W/cm².

At operation 204 a, after the silicon and nitrogen containing layer isdeposited in operation 203, the flow of the silicon-containing gas andthe first-nitrogen containing gas is discontinued. At operation 204 b asecond nitrogen-containing gas is flowed into the chamber 100 at asecond flow rate higher than the first total flow rate. The secondnitrogen-containing gas is diatomic nitrogen gas (N₂), and in someembodiments is flowed into the chamber 100 at. the second flow rate ofabout 10000 sccm to about 20000 sccm. A space velocity of the N₂ of thesecond nitrogen-containing gas is about 4.0 min⁻¹ to about 130.0 min⁻¹.In one embodiment, at operation 204 b, argon (Ar) is flowed in to thechamber 100 at a second argon flow rate of about 7000 sccm to about 8000sccm.

At operation 205, the silicon and nitrogen containing layer is treated.A second RF power is applied to the second-nitrogen containing gas atthe first frequency of 10 MHz to about 20 MHz and at a second powerlevel. The second RF power may be applied for about 5 seconds to about20 seconds at a second pressure of the chamber 100 higher than the firstpressure of the chamber 100. In one example, the second pressure is lessthan 6 torr. The second power level may be in a range of about 80 W toabout 120 W. The second RF power is applied at a power density of about0.08 W/cm² to about 0.3 W/cm². The second power level is higher than thefirst power level.

At operation 206, a determination is made as to whether the cyclicdeposition-treatment process is repeated. Such a made determination maybe based, for example, on whether a film with a predetermined thicknessis formed, such as about 100 Å to about 800 Å. In one embodiment, thesilicon and nitrogen containing layer formed by the method 200 has astress of about −1.00 gigapascal (GPa) to about −2.00 GPa, a density of2.50 g/cm³ to about 3.50 g/cm³, a refractive index of 1.50 to 2.50, anda wet etch rate of about 6.00 angstrom per minute (Å/min) to about 7.00Å/min. The stress, the density, the refractive index, and the wet etchrate of the silicon and nitrogen containing layer formed by the method200 are substantially equivalent to a stress, a density, a refractiveindex, and a wet etch rate of a silicon and nitrogen containing layerformed by atomic layer deposition (ALD). However, in some embodiments,at least 15 substrates per hour may be processed via the method 200. Inone embodiment, 25 substrates per hour may be processed via the method200. In contrast, substrate throughput using ALD is generally lower.

Additionally, the method 200 may further include a first oxygen-dopingprocess or a second oxygen-doping process to optimize the etch rate ofthe silicon nitride film while not converting the film to a siliconoxynitride film. In one example of a first oxygen-doping process, atoperation 204 b an oxygen-containing gas is flowed into the chamber 100,and the second RF power is applied to the oxygen-containing gas duringtreatment at operation 205. In a second oxygen doping process, theoxygen-containing gas is flowed after the treatment of operation 205 andthe second RF power is applied for about 2 seconds to about 10 secondsat the second pressure. The oxygen-containing gas can include nitrousoxide (N₂O) and/or oxygen gas (O₂). A flow rate of N₂O may be about 50sccm to about 800 sccm and a flow rate of the O₂ may be about 10 sccm toabout 1,000 sccm. A space velocity of the oxygen-containing gas is about0.003 min⁻¹ to about 12.0 min⁻¹. The second RF power is applied at thefirst frequency of 10 MHz to about 20 MHz and at the second power level.Furthermore, the layers may be UV cured after treatment to furtherdensify the film.

FIG. 3 is a flow diagram of a method 300 for forming a film tailored tothe properties of an underlying layer, the use of the film as a hardmask, and the etch chemistries to be used on the film. To facilitateexplanation, FIG. 3 will be described with reference to FIG. 1. However,it is to be noted that a chamber other than chamber 100 of FIG. 1 may beutilized in conjunction with method 300.

At operation 301, a substrate 101 having a surface is disposed in achamber 100. In one embodiment, the substrate 101 is disposed on thesupport surface 107 of the substrate support 106, the support surface107 at a process distance 126 from the showerhead 114. The processdistance 126 is about 250 millimeters (mm) to about 350 mm. The processdistance 126 increases ion bombardment to densify the film. In oneembodiment, the substrate support is heated to about 300 degrees Celsius(° C.) to about 500° C. The substrate may optionally be ammonia (NH₃)soaked after operation 201 by flowing about 200 sccm to about 600 sccmof NH₃ for about 10 seconds to about 30 seconds.

At operation 302, a first process gas set comprising asilicon-containing gas and a first nitrogen-containing gas is flowedinto the chamber 100. The first process gas set is diatomic hydrogengas-free and may also include an inert gas. The silicon-containing gascan include silane (SH₄), and/or dimers and oligomers of silane. In oneembodiment, the flow controller 118 controls the flow rate of the firstprocess gas set from the gas source 116, and the showerhead 114distributes the first process gas set across the processing volume 104.The silicon-containing gas is flowed into the chamber 100 at a flow rateof about 10 to about 50 sccm. The first nitrogen-containing gas includesammonia (NH₃) and diatomic nitrogen gas (N₂). The NH₃ of the firstnitrogen-containing gas is flowed at a flow rate of about 100 sccm toabout 200 sccm and the diatomic nitrogen gas of the firstnitrogen-containing gas is flowed at a flow rate of about 1000 sccm toabout 3000 sccm. The inert gas can include argon (Ar) with a flow rateof 2000 sccm to about 4000 sccm. In the chamber 100, a space velocity ofthe silicon-containing gas is about 0.003 min⁻¹ to about 0.4 min⁻¹, aspace velocity of the NH₃ of the first nitrogen-containing gas is about0.03 min⁻¹ to about 1.3 min⁻¹, a space velocity of the N₂ of the firstnitrogen-containing gas is about 0.3 min⁻¹ to about 19 min-1, and aspace velocity of the inert gas is about 0.5 min⁻¹ to about 25 min⁻¹.

At operation 303, an initiation layer of about 5 Å to about 50 Å isdeposited. The initiation layer provides for a film with an idealsurface roughness, adhesion of the bulk deposited layer, and plasmastability, as low process gas flow can result in plasma instability. Athird RF power is applied to the first process gas set at a secondfrequency and the third power level. The third RF power is applied forduration of about 10 seconds to about 20 seconds at a first pressure ofthe chamber about 2 torr to about 8 torr. In one embodiment, the RFpower source 122 provides RF energy to the showerhead 114 to facilitategeneration of plasma between the showerhead 114 and the substratesupport 106. The second frequency and third power level are less thanabout 500 kHz and about 50 W to about 100 W, respectively. The third RFpower is applied at a power density of about 0.05 W/cm² to about 0.25W/cm².

At operation 304 a, after the initiation layer is deposited, the flow ofthe first nitrogen-containing gas is discontinued. Operation 304 bincludes flowing a second process gas set comprising thesilicon-containing gas, a second nitrogen-containing gas, and ahydrogen-containing gas into the chamber 100. The second process gas setis diatomic nitrogen gas-free and may also include an inert gas. In oneexample, the silicon-containing gas includes silane (SiH₄) with a flowrate of about 10 sccm to about 50 sccm, the second nitrogen-containinggas includes ammonia (NH₃), and the hydrogen-containing gas includesdiatomic hydrogen (H₂) with a flow rate of 3000 sccm to about 4000 sccm.H₂ breaks Si—H bonds to remove in-film hydrogen and create danglingbonds while nitrogen-containing gas reacts with the active surface(e.g., the dangling bonds) of the substrate to create Si—Si bonds andSi—N bonds to form a nitrogen-rich film. The inert gas can include Arwith a flow rate of about 2000 sccm to about 4000 sccm. In the chamber100 the space velocity of the silicon-containing gas is about 0.003min⁻¹ to about 0.4 min⁻¹, a space velocity of the secondnitrogen-containing gas is about 0.4 min⁻¹ to about 13 min⁻¹, a spacevelocity of the hydrogen-containing gas is about 1.0 min⁻¹ to about 26min⁻¹, and the space velocity of the inert gas is about 0.7 min⁻¹ toabout 26 min⁻¹.

At operation 305, a bulk silicon nitride layer of about 100 Å to about700 Å is deposited. The first RF power is applied to the second processgas set at the first frequency and the first power level. The firstfrequency is higher than the second frequency and the first power levelhigher than the third power level. The first RF power may be applied forabout 200 seconds to about 300 seconds at a second pressure of thechamber 100 substantially the same as the pressure in the chamber 100during the depositing of the initiation layer. The first frequency is 10MHz to about 20 MHz and the first power level is about 50 W to about 100W. The first RF power is applied at a power density of about 0.05 W/cm²to about 0.25 W/cm². It is believed that increasing the power andfrequency applied to the process gas as compared to operation 303 canincrease ion bombardment and densify the film.

The disclosed silicon nitride film by bulk deposition process forms thesilicon and nitrogen containing film including the initiation layer andthe bulk silicon nitride layer. The silicon and nitrogen containing filmis formed with a predetermined thickness, such as about 100 Å to about800 Å. In one embodiment, the silicon and nitrogen containing filmformed by the method 300 has a stress of about −1.00 gigapascal (GPa) toabout −2.00 GPa, a density of about 2.50 g/cm³ to about 3.50 g/cm³, arefractive index of about 1.50 to about 2.50, and a wet etch rate ofabout 6.00 angstrom per minute (Å/min) to about 7.00 Å/min. The stress,the density, the refractive index, and the wet etch rate of the siliconand nitrogen containing film formed by the method 300 are substantiallyequivalent to a stress, a density, a refractive index, and a wet etchrate of a silicon and nitrogen containing layer formed by atomic layerdeposition (ALD). However, in some embodiments, at least 15 substratesper hour may be processed via the method 300.

The method 300 can include two transition processes, transitioning fromthe depositing the initiation layer at operation 303, and transitioningto the depositing the bulk silicon nitride layer, in order to transitionfrom the first process gas set to the second process gas set and fromthe third RF power to the first RF power. Transitioning from thedepositing the initiation layer includes applying a fourth RF power atthe first frequency and a fourth power level, and the third RF power atthe second frequency and third power level to the first process gas setfor a duration of about 1 second to about 3 seconds. The fourth powerlevel is about 25 W to about 75 W. The third power level is higher thanthe fourth power level. The fourth RF power is applied at a powerdensity of about 0.02 W/cm² to about 0.2 W/cm².

Transitioning to depositing the bulk silicon nitride layer includesapplying the first RF power at the first frequency and the first powerlevel, and a fifth RF power at the second frequency and a fifth powerlevel of about 15 W to about 45 W to the first process gas set for aduration of about 1 second to about 3 seconds. The flow rate of thefirst nitrogen-containing gas during the transitioning from thedepositing the initiation layer is higher than a flow rate of the firstnitrogen-containing gas at the transitioning to the depositing of thebulk silicon nitride layer. The fifth RF power is applied at a powerdensity of about 0.015 W/cm² to about 0.12 W/cm².

Additionally, the method 300 may further include oxygen-doping theinitiation layer by flowing an oxygen-containing gas into the chamber100 at operation 302 and applying the third RF power to theoxygen-containing gas at operation 303. The oxygen-containing gas caninclude nitrous oxide (N₂O) and/or oxygen gas (O₂). At operation 302, aflow rate of N₂O may be about 40 sccm to about 1,000 sccm and a flowrate of the O₂ may be about 10 sccm to about 1,000 sccm. At operation302, a space velocity of the oxygen-containing gas is about 0.003 min⁻¹to about 12 min⁻¹. The bulk silicon nitride layer may also beoxygen-doped by flowing the oxygen-containing gas into the chamber 100at operation 304 b and applying the first RF power to theoxygen-containing gas at operation 205. At operation 304 b, the flowrate of N₂O may be about 40 sccm to about 1,000 sccm and the flow rateof the O₂ may be about 10 sccm to about 1,000 sccm. At operation 304 b,the space velocity of the oxygen-containing gas is about 0.003 min⁻¹ toabout 12 min⁻¹. Additionally, the film may be UV cured at variousthicknesses during operation 305 to further densify the film.

FIG. 4 is a flow diagram of a method 400 for forming a film tailored tothe properties of an underlying layer, the use of the film as a hardmask, and the etch chemistries to be used on the film. To facilitateexplanation, FIG. 4 will be described with reference to FIG. 1. However,it is to be noted that a chamber other than chamber 100 of FIG. 1 may beutilized in conjunction with method 400.

At operation 401, a substrate 101 having a surface is disposed in achamber 100. In one embodiment, the substrate 101 is disposed on thesupport surface 107 of the substrate support 106, the support surface107 at a process distance 126 from the showerhead 114. The processdistance 126 is about 250 millimeters (mm) to about 350 mm. The processdistance 126 increases ion bombardment to densify the film. In oneembodiment, the substrate support is heated to about 300 degrees Celsius(° C.) to about 500° C. The substrate may optionally be NH₃ soaked afteroperation 401 by flowing about 200 sccm to about 600 sccm of ammonia(NH₃) for about 10 seconds to about 30 seconds.

At operation 402, a first process gas set comprising asilicon-containing and a first nitrogen-containing gas is flowed intothe chamber 100 at a first total flow rate. In one embodiment, the flowcontroller 118 controls the flow rate of the first process gas set fromthe gas source 116 and the showerhead 114 distributes the first processgas set across the processing volume 104. The silicon-containing gas caninclude silane (SH₄) and/or dimers and oligomers of silane with a flowrate of about 10 sccm to about 50 sccm. The first nitrogen-containinggas includes ammonia (NH₃) and diatomic nitrogen gas (N₂). The ammoniaof the first gas set is flowed at a flow rate of about 750 sccm to about1500 sccm and the nitrogen-containing gas of the first gas set is flowedat a flow rate of about 1000 sccm to about 3000 sccm. In the chamber 100a space velocity of the silicon-containing gas is about 0.003 min⁻¹ toabout 0.4 min⁻¹, a space velocity of the NH₃ of the firstnitrogen-containing gas is about 0.25 min⁻¹ to about 10 min⁻¹, and aspace velocity of the N₂ of the first nitrogen-containing gas is about0.35 min⁻¹ to about 20 min⁻¹.

At operation 403, a silicon and nitrogen containing layer of about 5 Åto 50 Å is deposited. During the deposition, the first RF power isapplied to the first process gas set at the first frequency and thefirst power level. In one embodiment, the RF power source 122 providesRF energy to the showerhead 114 to facilitate generation of plasmabetween the showerhead 114 and the substrate support 106. The first RFpower may be applied for about 1 second to about 5 seconds at a firstpressure of the chamber, which is less than 8 torr. The first frequencyis about 10 MHz to about 20 MHz and the first power level is about 50 Wto about 100 W. The first power is applied at a power density of about0.05 to about 0.25.

At operation 404 a, after the silicon and nitrogen containing layer isdeposited, the flow of the first process gas set is discontinued. Atoperation 404 b a second process gas set comprising a secondnitrogen-containing gas is flowed into the chamber 100 at a second totalflow rate higher than the first total flow rate. The firstnitrogen-containing gas is diatomic nitrogen gas (N₂) with a flow rateof about 10000 sccm to about 20000 sccm. A space velocity of the N₂ ofthe second nitrogen-containing gas is about 3.5 min⁻¹ to about 128min⁻¹.

At operation 405, the silicon and nitrogen containing layer is treated.The second RF power is applied to the second-nitrogen containing gas atthe first frequency of about 10 MHz to about 20 MHz and the second powerlevel. The second RF power may be applied for about 5 seconds to about20 seconds at a second pressure of the chamber higher than the firstpressure of the chamber during the deposition of the silicon and nitridelayer. The second pressure is less than 8 torr and the second powerlevel is about 80 W to about 120 W. The second power level is higherthan the first power level.

At operation 406, a determination is made as to whether the cyclicdeposition-treatment process is repeated. Such a made determination maybe based, for example, on whether a first initiation layer with apredetermined thickness is formed, such as about 5 Å to about 50 Å.Additionally, the method 400 may further include a first oxygen-dopingprocess or a second oxygen-doping process to optimize the etch rate ofthe silicon nitride film while not converting film to a siliconoxynitride film. In a first oxygen-doping process, at operation 404 b anoxygen-containing gas is flowed into the chamber 100 and the second RFpower is applied to the oxygen-containing gas during treatment atoperation 405. In a second oxygen doping process, the oxygen-containinggas is flowed after treatment of operation 405 and the second RF poweris applied after treatment for about 2 seconds to about 10 seconds. Theoxygen-containing gas can include nitrous oxide (N₂O) and/or oxygen gas(O₂). A flow rate of N₂O may be about 50 sccm to about 800 sccm and aflow rate of the O₂ gas may be about 10 sccm to about 1,000 sccm. Aspace velocity of the oxygen-containing gas is about 0.003 min⁻¹ toabout 12 min⁻¹. The second RF power is applied at the first frequencyand the second power level. Furthermore, the layers may be UV curedafter treatment to further densify the film.

After the first initiation layer is formed in operation 406, atoperation 407 a the second process gas set is discontinued and atoperation 407 b a third process gas set comprising thesilicon-containing gas, a third nitrogen-containing gas, and ahydrogen-containing gas is flowed into the chamber 100. In oneembodiment, operation 407 a and operation 407 b occur simultaneously.The third process gas set is diatomic nitrogen gas-free and may alsoinclude an inert gas. In one example, the silicon-containing gasincludes silane (SiH_(')) with a flow rate of about 10 sccm to about 50sccm, the third nitrogen-containing gas includes ammonia (NH₃), and thehydrogen-containing gas includes H₂ with a flow rate of 3000 sccm toabout 4000 sccm. The inert gas can include Ar with a flow rate of 2000sccm to about 4000 sccm. In the chamber 100, the space velocity of thesilicon-containing gas is about 0.003 min⁻¹ to about 0.4 min⁻¹, a spacevelocity of the third nitrogen-containing gas is about 0.25 min⁻¹ toabout 10 min⁻¹, a space velocity of the hydrogen-containing gas is about1 min⁻¹ to about 26 min⁻¹, and a space velocity of the inert gas isabout 0.7 min⁻¹ to about 26 min⁻¹.

At operation 408, a bulk silicon nitride layer of about 100 Å to about700 Å is deposited. The first RF power is applied to the third processgas set at the first frequency and the first power level. The first RFpower may be applied for about 200 seconds to about 300 seconds at athird pressure of the chamber lower than the second pressure of thechamber during treatment of the silicon and nitrogen containing layer.The first frequency is about 10 MHz to about 20 MHz and the first powerlevel may be about 50 W to about 100 W. The first power is applied at apower density of about 0.05 to about 0.25.

The disclosed silicon nitride film deposition process forms the siliconand nitrogen containing film comprising at least a first initiationlayer and the bulk silicon nitride layer. The silicon and nitrogencontaining film is formed with a predetermined thickness, such as about100 Å to about 800 Å. In one embodiment, the silicon and nitrogencontaining film formed by the method 400 has a stress of about −1.00gigapascal (GPa) to about −2.00 GPa, a density of about 2.50 g/cm³ toabout 3.50 g/cm³, a refractive index of about 1.50 to about 2.50, and awet etch rate of about 6.00 angstrom per minute (Å/min) to about 7.00Å/min. The stress, the density, the refractive index, and the wet etchrate of the silicon and nitrogen containing film formed by the method300 are substantially equivalent to a stress, a density, a refractiveindex, and a wet etch rate of a silicon and nitrogen containing layerformed by ALD. However, in some embodiments, at least 15 substrates perhour may be processed via the method 300.

The method 400 may further include depositing a second initiation layerbefore depositing the bulk silicon nitride layer. In operation 407 a,after the flow of the second process gas set is discontinued and beforethe third process gas set is flowed, a fourth process gas set comprisingthe silicon-containing gas and the first nitrogen-containing gas isflowed into the process chamber. The first process gas set is diatomichydrogen gas-free and may also include the inert gas. Thesilicon-containing gas includes silane (SH₄) and/or dimers and oligomersof silane, and the flow rate of the silicon-containing gas may be about10 to about 50 sccm. The first nitrogen-containing gas includes ammonia(NH₃) and diatomic nitrogen gas (N₂). In some embodiments, the ammoniaof the first nitrogen-containing gas is flowed the a flow rate of about100 sccm to about 200 sccm and the diatomic nitrogen gas of the firstnitrogen-containing gas is flowed at the flow rate of about 1000 sccm toabout 3000 sccm. The inert gas can include Ar with the flow rate of 2000sccm to about 4000 sccm. In the chamber 100, the space velocity of thesilicon-containing gas is about 0.003 min⁻¹ to about 0.4 min⁻¹, thespace velocity of the NH₃ of the first nitrogen-containing gas is about0.03 min⁻¹ to about 3 min⁻¹, the space velocity of the N₂ of the firstnitrogen-containing gas is about 0.35 min⁻¹ to about 19 min-1, and thespace velocity of the inert gas is about 0.7 min⁻¹ to about 26 min⁻¹.

The second initiation layer is deposited by applying the third RF powerto the fourth process gas set at the second frequency less than 500 kHzand a third power level of about 50 W to about 100 W to deposit a secondinitiation layer of about 5 Å to 50 Å. The third RF power is applied fora duration of about 10 seconds to about 20 seconds at the third pressureof the chamber. The third RF power is applied at a power density ofabout 0.05 W/cm² to about 0.25 W/cm².

After the deposition of the second initiation layer, the method 400 mayinclude two transition processes, transitioning from the depositing thefirst initiation layer and transitioning to the depositing the bulksilicon nitride layer, in order to transition from the fourth processgas set to third process gas set and from the third RF power to thefirst RF power. Transitioning from the depositing the initiation layerincludes applying the fourth RF power at the first frequency and thefourth power level of about 25 W to about 75 W, and the third RF powerat the second frequency and third power level to the fourth process gasset for a duration of about 1 second to about 3 seconds. The third powerlevel is higher than the fourth power level.

Transitioning to the depositing the bulk silicon nitride layer includesapplying the first RF power at the first frequency and the first powerlevel, and the fifth RF power at the second frequency and the fifthpower level of about 15 W to about 45 W to the first process gas set fora duration of about 1 second to about 3 seconds. The flow rate of thefirst nitrogen-containing gas during the transitioning from thedepositing the initiation layer is higher than a flow rate of the firstnitrogen-containing gas at the transitioning to the depositing of thebulk silicon nitride layer. After the transitioning to the depositingthe flow of the fourth process gas set is discontinued.

Additionally, method 400 may further include oxygen-doping the secondinitiation layer by flowing an oxygen-containing gas into the processchamber at operation 407 a, after the flow of the second process gas setis discontinued and before the third process gas set is flowed. Duringthe oxygen doping, the third RF power is applied to an oxygen-containinggas while the second initiation layer is deposited. Theoxygen-containing gas can include nitrous oxide (N₂O) and/or oxygen gas(O₂). To oxygen-dope the second initiation layer, a flow rate of N₂O maybe about 40 sccm to about 1,000 sccm and a flow rate of the O₂ may beabout 10 sccm to about 1,000 sccm. A space velocity of theoxygen-containing gas is about 0.003 min⁻¹ to about 13 min⁻¹ tooxygen-dope the second initiation layer. The bulk silicon nitride layermay also be oxygen-doped by flowing the oxygen-containing gas into theprocess chamber at operation 408 and applying the second RF power to theoxygen-containing gas at operation 408. At process 408, the flow rate ofN₂O may be about 40 sccm to about 1,000 sccm and the flow rate of the O₂may be about 10 sccm to about 1,000 sccm. At operation 408, the spacevelocity of the oxygen-containing gas is about 0.003 min⁻¹ to about 13min⁻¹. Additionally, the film may be UV cured at various thicknessesduring operation 408 to further densify the film.

In an exemplary embodiment, a 300 mm circular semiconductor substrate isdisposed in a chamber 100 having a process volume of 1.4 L. Thesilicon-containing gas is SiH₄ with a space velocity of about 0.01 min⁻¹and flow rate of about 30 sccm. The first nitrogen-containing gasincludes NH₃ with a space velocity of about 0.7 min⁻¹ and flow rate ofabout 50 sccm. Ar is flowed into the chamber 100 at a flow rate of about3000 sccm. H₂ at a space velocity of about 0.7 min⁻¹ and flow rate ofabout 1000 sccm is flowed into the chamber 100. The first RF power isapplied for about 4 seconds to the silicon and the first-nitrogencontaining gas, Ar, and H₂ at a frequency of about 13.56 MHz and powerlevel of about 80 W. The first pressure of the chamber 100 is about 2.2torr. The flow of the second nitrogen-containing includes about 11000sccm N₂ at a space velocity of about 10.7 min⁻¹ Ar is flowed into thechamber 100 at a flow rate of about 7600 sccm. The second RF power isapplied for about 13 seconds to the nitrogen-containing gas and the Arat the frequency of about 13.56 MHz and power level of about 100 W. Thesecond pressure of the chamber is about 4 torr. Repeating the cyclicdeposition-treatment process for 25 cycles forms a film with apredetermined thickness of about 330 Å. The film of about 330 Å has astress of about −1.32 GPa, a density of about 2.50 g/cm³, a refractiveindex of about 2.0002, and a wet etch rate of about 6.5 Å/min. About 16substrates per hour may be processed via the exemplary embodimentforming the film of about 330 Å. Repeating the cyclicdeposition-treatment process for 41 cycles forms a film with apredetermined thickness of about 660 Å. The film of about 660 Å has astress of about _ GPa, a density of about 2.995 g/cm³, a refractiveindex of about _, and a wet etch rate of about _ Å/min. About 25substrates per hour may be processed via the exemplary embodimentforming the film of about 660 Å. In another embodiment using the samesubstrate configuration and process volume, the substrate is first NH₃soaked by a flow of 400 sccm of NH₃ for about 20 seconds. Then, the flowof the first process gas set includes about 50 sccm of SiH₄ at a spacevelocity of about 0.04 min⁻¹, about 150 sccm of NH₃ at a space velocityof about 0.1 min⁻¹, about 2000 sccm of N₂ at a space velocity of about1.4 min⁻¹, and about 2000 sccm of Ar at a space velocity of about 1.4min⁻¹. The third RF power is applied for about 15 seconds to the firstprocess gas set at the second frequency of about 300 kHz and first powerlevel of about 75 W. The first pressure of the chamber is about 2 torrto deposit an initiation layer with a thickness of about 20 Å.Transitioning from the depositing the initiation layer includes applyingthe fourth RF power at the frequency of about 300 kHz and the fourthpower level of about 50 W and the third RF power at the frequency ofabout 13.56 MHz and third power level to the first process gas set for aduration of about 1 second. The flow rate of NH₃ is about 150 sccm andthe flow rate of N₂ is about 2000 sccm during the transitioning from thedepositing the initiation layer.

Transitioning to the depositing the bulk silicon nitride layer includesfirst applying the third RF power at the frequency of about 13.56 MHzand the first power level of about 80 W and the fifth RF power at thefrequency of about 300 kHz and the fifth power level of about 30 W tothe first process gas set for a duration of about 1 second. The flowrate of NH₃ is about 100 sccm and the flow rate of N₂ is about 1000 sccmduring the transitioning to the depositing of the bulk silicon nitridelayer.

The flow of the second process gas set includes about 50 sccm of SiH₄ ata space velocity of about 0.04 min⁻¹, about 100 sccm of NH₃ at a spacevelocity of about 0.07 min⁻¹, and about 3500 sccm of H₂ at a spacevelocity of about 2.5 min⁻¹. A bulk silicon nitride layer of about 200 Åis deposited by applying for duration of about 217 seconds the first RFpower to the second process gas set at the frequency of about 13.56 MHzand second power level of about 80 W. The second pressure of the chamberis about 2 torr. A film with a predetermined thickness of about 220 Å isformed.

In another embodiment using the same substrate configuration and processvolume, the substrate is NH₃ soaked by a flow of about 400 sccm of NH₃for about 20 seconds. The flow of the first process gas set includesabout 12 sccm of SiH₄ at a space velocity of about 0.008 min⁻¹, about1000 sccm of NH₃ at a space velocity of about 0.7 min⁻¹, and about 1000sccm of N₂ at a space velocity of about 0.009 min⁻¹. The first RF poweris applied for about 2 seconds to the first process gas set at afrequency of about 13.56 MHz and power level of about 80 W. The firstpressure of the process chamber is about 3 torr. The flow of the secondprocess gas set includes about 15000 sccm N₂ at a space velocity ofabout 10.7 min⁻¹ and a flow of about 500 sccm N₂O at a space velocity ofabout 10.7 min⁻¹ is additionally flowed. The second RF power is appliedfor about 10 seconds to the nitrogen-containing gas and the N₂O at thefrequency of about 13.56 MHz and power level of 100 W. The secondpressure of the chamber is about 4 torr. The layers are UV cured aftertreatment to further densify the film. The cyclic deposition-treatmentprocess is repeated until a first initiation layer with a predeterminedthickness of about 10 Å is formed.

The flow of the fourth process gas set includes about 50 sccm of SiH₄ ata space velocity of 0.04 min⁻¹, about 150 sccm of NH₃ at a spacevelocity of about 0.11 min⁻¹, 2000 sccm of N₂ at a space velocity ofabout 1.4 min⁻¹, and about 2000 sccm of Ar at a space velocity of about1.4 min⁻¹. The first RF power is applied for 2 seconds to the fourthprocess gas set at the frequency of about 300 kHz and first power levelof about 80 W. The first pressure of the chamber is about 2 torr todeposit a second initiation layer with thickness of about 10 Å.

Transitioning from the depositing the second initiation layer includesapplying the fourth RF power at the first frequency of about 13.56 MHzand the fourth power level of about 50 W and the third RF power at thefrequency of about 300 kHz and third power level to the fourth processgas set for a duration of about 1 second. The flow rate of NH₃ is about150 sccm and the flow rate of N₂ is about 2000 sccm during thetransitioning from the depositing the initiation layer. Transitioning tothe depositing the bulk silicon nitride layer includes applying thefirst RF power at the frequency of about 13.56 MHz and the first powerlevel of about 80 W and a fifth RF power at the frequency of about 300kHz and the fifth power level of about 30 W to the fourth process gasset for a duration of about 1 second. The flow rate of NH₃ is about 100sccm and the flow rate of N₂ is about 1000 sccm during the transitioningto the depositing of the bulk silicon nitride layer.

The flow of the third process gas set includes 50 about sccm of SiH₄ ata space velocity of about 0.04 min⁻¹, about 100 sccm of NH₃ at a spacevelocity of about 0.07 min⁻¹, about 3000 sccm of H₂ at a space velocityof 2.1 min⁻¹, and about 3000 sccm of Ar at a space velocity of 2.1min⁻¹. A bulk silicon nitride layer of about 200 Å is deposited byapplying for duration of about 217 seconds the first RF power to thethird process gas set at the frequency of about 13.56 MHz and firstpower level of about 80 W. The second pressure of the chamber is about 2torr to deposit the bulk silicon nitride layer. A film with apredetermined thickness of about 220 Å is formed.

In summation, a PECVD process that forms silicon and nitride containingfilms having substantially equivalent stresses, densities, refractiveindices, and wet etch rates of silicon and nitride containing filmsformed by ALD is disclosed. The PECVD processes enable throughput of atleast 16 substrates per hour.

While the foregoing is directed to examples of the present disclosure,other and further examples of the disclosure may be devised withoutdeparting from the basic scope thereof, and the scope thereof isdetermined by the claims that follow.

What is claimed is:
 1. A method for forming a silicon nitride film,comprising: disposing a substrate including a surface in a chamber;flowing a silicon-containing gas and a first nitrogen-containing gasinto the chamber at a first total flow rate; depositing a silicon andnitrogen containing layer on the surface of the substrate by applying afirst radio frequency (RF) power at a first power level to thesilicon-containing gas and the first nitrogen-containing gas;discontinuing the flow of the silicon-containing gas and the firstnitrogen-containing gas and flowing a second nitrogen-containing gasinto the chamber, wherein a flow rate of the second nitrogen-containinggas is higher than the first total flow rate; treating the silicon andnitrogen containing layer by applying a second RF power to the secondnitrogen-containing gas at a second power level higher than the firstpower level; and repeating the flowing the silicon-containing gas andthe first nitrogen-containing gas, the depositing the silicon andnitrogen containing layer, the discontinuing the flow of thesilicon-containing gas and the first nitrogen-containing gas and theflowing the second nitrogen-containing gas, and the treating the siliconand nitrogen containing layer until a film with a predeterminedthickness is formed.
 2. The method of claim 1, wherein thesilicon-containing gas comprises silane (SiH₄); the silicon-containinggas is flowed at a flow rate of about 10 standard cubic centimeters perminute (sccm) to about 50 sccm; the first nitrogen-containing gascomprises at least one of ammonia (NH₃) and diatomic nitrogen gas (N₂);the ammonia of the first nitrogen-containing gas is flowed at a flowrate of about 30 sccm to about 1500 sccm; the diatomic nitrogen gas ofthe first nitrogen-containing gas is flowed at a flow rate of about 500sccm to about 3000 sccm; the second nitrogen-containing gas comprisesdiatomic nitrogen gas (N₂); and the second nitrogen-containing gas isflowed at a flow rate about 10000 sccm to about 20000 sccm.
 3. Themethod of claim 1, wherein a pressure of the chamber is not greater than6 torr, and wherein the pressure in chamber during the treating of thesilicon and nitrogen containing layer is higher than the pressure in thechamber during the depositing of the silicon and nitrogen containinglayer.
 4. The method of claim 1, wherein the first power level is about50 Watts (W) to about 100 W; the first RF power is applied for aduration of about 1 second to about 5 seconds; the second power level isabout 80 W to about 120 W; and the second RF power is applied for aduration of about 5 seconds to 15 seconds.
 5. The method of claim 4,further comprising: flowing an oxygen-containing gas into the chamber;and applying the second RF power to the oxygen-containing gas during thetreating the silicon and nitrogen containing layer or applying thesecond RF power to the oxygen-containing gas after the treating thesilicon and nitrogen containing layer, wherein the second RF power afterthe treating the silicon and nitrogen containing layer is applied for aduration of about 2 seconds to about 10 seconds at the second powerlevel.
 6. A method for forming a silicon nitride film, comprising:disposing a substrate including a surface in a chamber; flowing a firstprocess gas set comprising a silicon-containing gas and a firstnitrogen-containing gas into the chamber, wherein the first process gasset is diatomic hydrogen gas-free; depositing an initiation layer on thesurface of the substrate by applying a third radio frequency (RF) powerto the first process gas set at a second frequency and a third powerlevel; discontinuing the flowing the first nitrogen-containing gas ofthe first process gas set and flowing a second process gas setcomprising the silicon-containing gas, a second nitrogen-containing gas,and a hydrogen-containing gas into the chamber, wherein the secondprocess gas set is diatomic nitrogen gas-free; and depositing a bulksilicon nitride layer on the initiation layer by applying a first RFpower to the second process gas set at a first frequency higher than thesecond frequency and a first power level higher than the third powerlevel.
 7. The method of claim 6, wherein the silicon-containing gascomprises silane (SiH₄); while flowing the first process gas set, thesilicon-containing gas is flowed at a flow rate of about 10 standardcubic centimeters per minute (sccm) to about 50 sccm; the firstnitrogen-containing gas comprises ammonia (NH₃) and diatomic nitrogengas (N₂); while flowing the first process gas set, the ammonia is flowedat a flow rate of about 100 sccm to about 200 sccm and the diatomicnitrogen gas (N₂) is flowed at a flow rate of about 1000 to about 3000sccm; the second nitrogen-containing gas comprises ammonia (NH₃); whileflowing the second process gas set, the second nitrogen-containing gasis flowed at a flow rate about 100 sccm to about 200 sccm; thehydrogen-containing gas comprises diatomic hydrogen gas (H₂); and whileflowing the second process gas set, the hydrogen-containing gas isflowed at a flow rate of about 3000 sccm to 4000 sccm.
 8. The method ofclaim 6, wherein a pressure of the chamber is not greater than 8 torr,and wherein the pressure in chamber during the depositing of theinitiation layer is the same as the pressure in the chamber during thedepositing of the bulk silicon nitride layer.
 9. The method of claim 6,wherein the third power level is about 50 Watts (W) to about 100 W; thesecond frequency is less than 500 kilohertz (kHz); the third RF power isapplied for a duration of about 10 seconds to 20 seconds; the firstpower level is about 50 W to about 100 W; the first frequency is about10 megahertz (MHz) to about 20 MHz; and the first RF power is appliedfor a duration of about 200 seconds to 300 seconds.
 10. The method ofclaim 6, further comprising flowing about 200 sccm to about 600 sccm ofNH₃ prior to the flowing the first process gas set.
 11. The method ofclaim 6, further comprising flowing an oxygen-containing gas into thechamber and applying the third RF power to the oxygen-containing gas,wherein the third RF power is applied to the oxygen-containing gasduring the depositing the initiation layer.
 12. The method of claim 11,further comprising flowing the oxygen-containing gas into the chamberand applying the first RF power to the oxygen-containing gas, whereinthe first RF power is applied to the oxygen-containing gas during thedepositing of the bulk silicon nitride layer.
 13. The method of claim 6,further comprising: transitioning from the depositing the initiationlayer by applying a fourth RF power at the first frequency and a fourthpower level of about 25 W to about 75 W and the third RF power at thefirst frequency and the third power level to the first process gas setfor a duration of about 1 second to about 3 seconds, wherein the thirdpower level is higher than the fourth power level; and transitioning tothe depositing the bulk silicon nitride layer by applying the first RFat the first frequency and the first power level and a fifth RF power atthe first frequency and a fifth power level of about 15 W to about 45 Wto the first process gas set for a duration of about 1 second to about 3seconds, wherein a flow rate of the first nitrogen-containing gas duringthe transitioning from the depositing the initiation layer is higherthan a flow rate of the first nitrogen-containing gas at thetransitioning to the depositing of the bulk silicon nitride layer.
 14. Amethod for forming a silicon nitride film, comprising: disposing asubstrate including a surface in a chamber; flowing a first process gasset comprising a silicon-containing gas and a first nitrogen-containinggas into the chamber at a first total flow rate; depositing a siliconand nitride containing layer on the surface of the substrate by applyinga first radio frequency (RF) power to the first process gas set at afirst frequency of 10 megahertz (MHz) and 20 MHz and a first power levelof about 50 Watts (W) to about 100 W for a duration of about 1 second toabout 5 seconds at a first pressure of the chamber less than 8 torr;discontinuing the flow of the first process gas set; flowing a secondprocess gas set comprising a second nitrogen-containing gas into thechamber at a second total flow rate, wherein the second total flow rateis higher than the first total flow rate; treating the silicon andnitrogen containing layer by applying a second RF power at the firstfrequency and a second power level of about 80 W to about 120 W to thesecond process gas set for a duration of about 5 second to 15 seconds ata second pressure of the chamber, wherein the second power level ishigher than the first power level, and wherein the first pressure of thechamber is higher than the second pressure of the chamber; repeating theflowing the first process gas set, the depositing the silicon andnitride containing layer, the discontinuing the flow of the firstprocess gas set, the flowing the second process gas set, and thetreating of the silicon and nitrogen containing layer until a firstinitiation layer with a predetermined thickness is formed; discontinuingthe flow of the second process gas set and flowing a third process gasset comprising the silicon-containing gas, a third nitrogen-containinggas, and a hydrogen-containing gas into the chamber, wherein the thirdprocess gas set is diatomic nitrogen gas-free; and depositing a bulksilicon nitride layer on the first initiation layer by applying thefirst RF power to the third process gas set at the first frequency andthe first power level for a duration of about 200 to about 300 secondsat a third pressure of the chamber, wherein the second pressure of thechamber is higher than the third pressure of the chamber.
 15. The methodof claim 14, wherein the silicon-containing gas comprises silane (SiH₄);while flowing the first process gas set, the silicon-containing gas isflowed at a flow rate of about 10 standard cubic centimeters per minute(sccm) to about 50 sccm; the first nitrogen-containing gas comprisesammonia (NH₃) and diatomic nitrogen gas (N₂); while flowing the firstprocess gas set, the ammonia is flowed at a flow rate of about 750 sccmto about 1500 sccm and the diatomic nitrogen gas (N₂) is flowed at aflow rate of about 1000 to about 3000 sccm; the secondnitrogen-containing gas comprises diatomic nitrogen gas (N₂); whileflowing the second process gas set, the second nitrogen-containing gasis flowed at a flow rate about 10000 sccm to about 20000 sccm; the thirdnitrogen-containing gas comprises ammonia (NH₃); while flowing the thirdprocess gas set, the second nitrogen-containing gas is flowed at a flowrate about 100 sccm to about 200 sccm; the hydrogen-containing gascomprises diatomic hydrogen gas (H₂); and while flowing the thirdprocess gas set, the hydrogen-containing gas is flowed at a flow rate ofabout 3000 sccm to 4000 sccm.
 16. The method of claim 14, furthercomprising: flowing a fourth process gas set comprising thesilicon-containing gas and the first nitrogen-containing gas into thechamber, wherein the fourth process gas set in diatomic hydrogengas-free; depositing a second initiation layer by applying a third RFpower to the fourth process gas set at a second frequency less than 500kilohertz (kHz) and a third power level of about 50 W to about 100 W,wherein the first power level is higher than the third power level andthe first frequency is higher than the second frequency; transitioningfrom the depositing the second initiation layer by applying a fourth RFpower at the first frequency and a fourth power level of about 25 W toabout 75 W and the third RF power at the first frequency and the thirdpower level to the fourth process gas set for a duration of about 1second to about 3 seconds, wherein the third power level is higher thanthe fourth power level; transitioning to the depositing the bulk siliconnitride layer by applying the first RF at the first frequency and thefirst power level and a fifth RF power at the first frequency and afifth power level of about 15 W to about 45 W to the fourth process gasset for a duration of about 1 second to about 3 seconds, wherein a flowrate of the first nitrogen-containing gas during the transition from thedepositing the second initiation layer is higher than a flow rate of thefirst nitrogen-containing gas at the transitioning to the depositing ofthe bulk silicon nitride layer; and discontinuing the flow of the fourthprocess gas set.
 17. The method of claim 16, further comprising flowingan oxygen-containing gas into the chamber and applying the third RFpower to the oxygen-containing gas, wherein the third RF power isapplied to the oxygen-containing gas during the depositing of the secondinitiation layer.
 18. The method of claim 14, further comprising flowingabout 200 sccm to about 600 sccm of ammonia (NH₃) prior to the flowingthe first process gas set.
 19. The method of claim 14, furthercomprising: flowing an oxygen-containing gas into the chamber; andapplying the second RF power to the oxygen-containing gas during thetreating the silicon and nitrogen containing layer or applying thesecond RF power to the oxygen-containing gas after the treating thesilicon and nitrogen containing layer, wherein the second RF power isapplied for a duration of about 2 seconds to about 10 seconds at thesecond power level.
 20. The method of claim 19, further comprisingflowing the oxygen-containing gas into the chamber and applying thefirst RF power to the oxygen-containing gas, wherein the first RF poweris applied to the oxygen-containing gas during the depositing of thebulk silicon nitride layer.